Give Back My Money

I have been with Discovery Insure since 2021 and I have been singing their praises until recently when I had to leave them because I could not afford their premiums anymore. In early April I was sent my renewal notice advising that my premium would increase from May. I pay my insurance in advance meaning the premium to cover me from 01 May 2024 - 31 May 2024 goes off on the 25th of April 2024. I allowed this debit to go off as normal while I shopped around and gave Discovery notice around the 12th of May 2024 that I would be leaving them on the 31st of May 2024. On the 25th of May 2024 they go and debit me for June, and when I ask them to refund that premium, they refund it in part stating "I enjoyed a few days of cover"... I am still trying to establish which few days of cover these are as I paid a full premium for May?? So as it stands, I have paid for insurance twice in the same month, with no cover. I have been going back a forth with different agents on email who seem to copy and paste the last person's response without reading what I am sending in the email. my Insurance does not run from the 25th, it runs from the first of the month as I am sure is the case with everyone's insurance. My payment date just happens to be my salary date.